diff options
Diffstat (limited to 'drivers/s390/char/sclp.c')
| -rw-r--r-- | drivers/s390/char/sclp.c | 915 |
1 files changed, 915 insertions, 0 deletions
diff --git a/drivers/s390/char/sclp.c b/drivers/s390/char/sclp.c new file mode 100644 index 000000000000..ceb0e474fde4 --- /dev/null +++ b/drivers/s390/char/sclp.c @@ -0,0 +1,915 @@ +/* + * drivers/s390/char/sclp.c + * core function to access sclp interface + * + * S390 version + * Copyright (C) 1999 IBM Deutschland Entwicklung GmbH, IBM Corporation + * Author(s): Martin Peschke <mpeschke@de.ibm.com> + * Martin Schwidefsky <schwidefsky@de.ibm.com> + */ + +#include <linux/module.h> +#include <linux/err.h> +#include <linux/spinlock.h> +#include <linux/interrupt.h> +#include <linux/timer.h> +#include <linux/reboot.h> +#include <linux/jiffies.h> +#include <asm/types.h> +#include <asm/s390_ext.h> + +#include "sclp.h" + +#define SCLP_HEADER "sclp: " + +/* Structure for register_early_external_interrupt. */ +static ext_int_info_t ext_int_info_hwc; + +/* Lock to protect internal data consistency. */ +static DEFINE_SPINLOCK(sclp_lock); + +/* Mask of events that we can receive from the sclp interface. */ +static sccb_mask_t sclp_receive_mask; + +/* Mask of events that we can send to the sclp interface. */ +static sccb_mask_t sclp_send_mask; + +/* List of registered event listeners and senders. */ +static struct list_head sclp_reg_list; + +/* List of queued requests. */ +static struct list_head sclp_req_queue; + +/* Data for read and and init requests. */ +static struct sclp_req sclp_read_req; +static struct sclp_req sclp_init_req; +static char sclp_read_sccb[PAGE_SIZE] __attribute__((__aligned__(PAGE_SIZE))); +static char sclp_init_sccb[PAGE_SIZE] __attribute__((__aligned__(PAGE_SIZE))); + +/* Timer for request retries. */ +static struct timer_list sclp_request_timer; + +/* Internal state: is the driver initialized? */ +static volatile enum sclp_init_state_t { + sclp_init_state_uninitialized, + sclp_init_state_initializing, + sclp_init_state_initialized +} sclp_init_state = sclp_init_state_uninitialized; + +/* Internal state: is a request active at the sclp? */ +static volatile enum sclp_running_state_t { + sclp_running_state_idle, + sclp_running_state_running +} sclp_running_state = sclp_running_state_idle; + +/* Internal state: is a read request pending? */ +static volatile enum sclp_reading_state_t { + sclp_reading_state_idle, + sclp_reading_state_reading +} sclp_reading_state = sclp_reading_state_idle; + +/* Internal state: is the driver currently serving requests? */ +static volatile enum sclp_activation_state_t { + sclp_activation_state_active, + sclp_activation_state_deactivating, + sclp_activation_state_inactive, + sclp_activation_state_activating +} sclp_activation_state = sclp_activation_state_active; + +/* Internal state: is an init mask request pending? */ +static volatile enum sclp_mask_state_t { + sclp_mask_state_idle, + sclp_mask_state_initializing +} sclp_mask_state = sclp_mask_state_idle; + +/* Maximum retry counts */ +#define SCLP_INIT_RETRY 3 +#define SCLP_MASK_RETRY 3 +#define SCLP_REQUEST_RETRY 3 + +/* Timeout intervals in seconds.*/ +#define SCLP_BUSY_INTERVAL 2 +#define SCLP_RETRY_INTERVAL 5 + +static void sclp_process_queue(void); +static int sclp_init_mask(int calculate); +static int sclp_init(void); + +/* Perform service call. Return 0 on success, non-zero otherwise. */ +static int +service_call(sclp_cmdw_t command, void *sccb) +{ + int cc; + + __asm__ __volatile__( + " .insn rre,0xb2200000,%1,%2\n" /* servc %1,%2 */ + " ipm %0\n" + " srl %0,28" + : "=&d" (cc) + : "d" (command), "a" (__pa(sccb)) + : "cc", "memory" ); + if (cc == 3) + return -EIO; + if (cc == 2) + return -EBUSY; + return 0; +} + +/* Request timeout handler. Restart the request queue. If DATA is non-zero, + * force restart of running request. */ +static void +sclp_request_timeout(unsigned long data) +{ + unsigned long flags; + + if (data) { + spin_lock_irqsave(&sclp_lock, flags); + sclp_running_state = sclp_running_state_idle; + spin_unlock_irqrestore(&sclp_lock, flags); + } + sclp_process_queue(); +} + +/* Set up request retry timer. Called while sclp_lock is locked. */ +static inline void +__sclp_set_request_timer(unsigned long time, void (*function)(unsigned long), + unsigned long data) +{ + del_timer(&sclp_request_timer); + sclp_request_timer.function = function; + sclp_request_timer.data = data; + sclp_request_timer.expires = jiffies + time; + add_timer(&sclp_request_timer); +} + +/* Try to start a request. Return zero if the request was successfully + * started or if it will be started at a later time. Return non-zero otherwise. + * Called while sclp_lock is locked. */ +static int +__sclp_start_request(struct sclp_req *req) +{ + int rc; + + if (sclp_running_state != sclp_running_state_idle) + return 0; + del_timer(&sclp_request_timer); + if (req->start_count <= SCLP_REQUEST_RETRY) { + rc = service_call(req->command, req->sccb); + req->start_count++; + } else + rc = -EIO; + if (rc == 0) { + /* Sucessfully started request */ + req->status = SCLP_REQ_RUNNING; + sclp_running_state = sclp_running_state_running; + __sclp_set_request_timer(SCLP_RETRY_INTERVAL * HZ, + sclp_request_timeout, 1); + return 0; + } else if (rc == -EBUSY) { + /* Try again later */ + __sclp_set_request_timer(SCLP_BUSY_INTERVAL * HZ, + sclp_request_timeout, 0); + return 0; + } + /* Request failed */ + req->status = SCLP_REQ_FAILED; + return rc; +} + +/* Try to start queued requests. */ +static void +sclp_process_queue(void) +{ + struct sclp_req *req; + int rc; + unsigned long flags; + + spin_lock_irqsave(&sclp_lock, flags); + if (sclp_running_state != sclp_running_state_idle) { + spin_unlock_irqrestore(&sclp_lock, flags); + return; + } + del_timer(&sclp_request_timer); + while (!list_empty(&sclp_req_queue)) { + req = list_entry(sclp_req_queue.next, struct sclp_req, list); + rc = __sclp_start_request(req); + if (rc == 0) + break; + /* Request failed. */ + list_del(&req->list); + if (req->callback) { + spin_unlock_irqrestore(&sclp_lock, flags); + req->callback(req, req->callback_data); + spin_lock_irqsave(&sclp_lock, flags); + } + } + spin_unlock_irqrestore(&sclp_lock, flags); +} + +/* Queue a new request. Return zero on success, non-zero otherwise. */ +int +sclp_add_request(struct sclp_req *req) +{ + unsigned long flags; + int rc; + + spin_lock_irqsave(&sclp_lock, flags); + if ((sclp_init_state != sclp_init_state_initialized || + sclp_activation_state != sclp_activation_state_active) && + req != &sclp_init_req) { + spin_unlock_irqrestore(&sclp_lock, flags); + return -EIO; + } + req->status = SCLP_REQ_QUEUED; + req->start_count = 0; + list_add_tail(&req->list, &sclp_req_queue); + rc = 0; + /* Start if request is first in list */ + if (req->list.prev == &sclp_req_queue) { + rc = __sclp_start_request(req); + if (rc) + list_del(&req->list); + } + spin_unlock_irqrestore(&sclp_lock, flags); + return rc; +} + +EXPORT_SYMBOL(sclp_add_request); + +/* Dispatch events found in request buffer to registered listeners. Return 0 + * if all events were dispatched, non-zero otherwise. */ +static int +sclp_dispatch_evbufs(struct sccb_header *sccb) +{ + unsigned long flags; + struct evbuf_header *evbuf; + struct list_head *l; + struct sclp_register *reg; + int offset; + int rc; + + spin_lock_irqsave(&sclp_lock, flags); + rc = 0; + for (offset = sizeof(struct sccb_header); offset < sccb->length; + offset += evbuf->length) { + /* Search for event handler */ + evbuf = (struct evbuf_header *) ((addr_t) sccb + offset); + reg = NULL; + list_for_each(l, &sclp_reg_list) { + reg = list_entry(l, struct sclp_register, list); + if (reg->receive_mask & (1 << (32 - evbuf->type))) + break; + else + reg = NULL; + } + if (reg && reg->receiver_fn) { + spin_unlock_irqrestore(&sclp_lock, flags); + reg->receiver_fn(evbuf); + spin_lock_irqsave(&sclp_lock, flags); + } else if (reg == NULL) + rc = -ENOSYS; + } + spin_unlock_irqrestore(&sclp_lock, flags); + return rc; +} + +/* Read event data request callback. */ +static void +sclp_read_cb(struct sclp_req *req, void *data) +{ + unsigned long flags; + struct sccb_header *sccb; + + sccb = (struct sccb_header *) req->sccb; + if (req->status == SCLP_REQ_DONE && (sccb->response_code == 0x20 || + sccb->response_code == 0x220)) + sclp_dispatch_evbufs(sccb); + spin_lock_irqsave(&sclp_lock, flags); + sclp_reading_state = sclp_reading_state_idle; + spin_unlock_irqrestore(&sclp_lock, flags); +} + +/* Prepare read event data request. Called while sclp_lock is locked. */ +static inline void +__sclp_make_read_req(void) +{ + struct sccb_header *sccb; + + sccb = (struct sccb_header *) sclp_read_sccb; + clear_page(sccb); + memset(&sclp_read_req, 0, sizeof(struct sclp_req)); + sclp_read_req.command = SCLP_CMDW_READDATA; + sclp_read_req.status = SCLP_REQ_QUEUED; + sclp_read_req.start_count = 0; + sclp_read_req.callback = sclp_read_cb; + sclp_read_req.sccb = sccb; + sccb->length = PAGE_SIZE; + sccb->function_code = 0; + sccb->control_mask[2] = 0x80; +} + +/* Search request list for request with matching sccb. Return request if found, + * NULL otherwise. Called while sclp_lock is locked. */ +static inline struct sclp_req * +__sclp_find_req(u32 sccb) +{ + struct list_head *l; + struct sclp_req *req; + + list_for_each(l, &sclp_req_queue) { + req = list_entry(l, struct sclp_req, list); + if (sccb == (u32) (addr_t) req->sccb) + return req; + } + return NULL; +} + +/* Handler for external interruption. Perform request post-processing. + * Prepare read event data request if necessary. Start processing of next + * request on queue. */ +static void +sclp_interrupt_handler(struct pt_regs *regs, __u16 code) +{ + struct sclp_req *req; + u32 finished_sccb; + u32 evbuf_pending; + + spin_lock(&sclp_lock); + finished_sccb = S390_lowcore.ext_params & 0xfffffff8; + evbuf_pending = S390_lowcore.ext_params & 0x3; + if (finished_sccb) { + req = __sclp_find_req(finished_sccb); + if (req) { + /* Request post-processing */ + list_del(&req->list); + req->status = SCLP_REQ_DONE; + if (req->callback) { + spin_unlock(&sclp_lock); + req->callback(req, req->callback_data); + spin_lock(&sclp_lock); + } + } + sclp_running_state = sclp_running_state_idle; + } + if (evbuf_pending && sclp_receive_mask != 0 && + sclp_reading_state == sclp_reading_state_idle && + sclp_activation_state == sclp_activation_state_active ) { + sclp_reading_state = sclp_reading_state_reading; + __sclp_make_read_req(); + /* Add request to head of queue */ + list_add(&sclp_read_req.list, &sclp_req_queue); + } + spin_unlock(&sclp_lock); + sclp_process_queue(); +} + +/* Return current Time-Of-Day clock. */ +static inline u64 +sclp_get_clock(void) +{ + u64 result; + + asm volatile ("STCK 0(%1)" : "=m" (result) : "a" (&(result)) : "cc"); + return result; +} + +/* Convert interval in jiffies to TOD ticks. */ +static inline u64 +sclp_tod_from_jiffies(unsigned long jiffies) +{ + return (u64) (jiffies / HZ) << 32; +} + +/* Wait until a currently running request finished. Note: while this function + * is running, no timers are served on the calling CPU. */ +void +sclp_sync_wait(void) +{ + unsigned long psw_mask; + unsigned long cr0, cr0_sync; + u64 timeout; + + /* We'll be disabling timer interrupts, so we need a custom timeout + * mechanism */ + timeout = 0; + if (timer_pending(&sclp_request_timer)) { + /* Get timeout TOD value */ + timeout = sclp_get_clock() + + sclp_tod_from_jiffies(sclp_request_timer.expires - + jiffies); + } + /* Prevent bottom half from executing once we force interrupts open */ + local_bh_disable(); + /* Enable service-signal interruption, disable timer interrupts */ + __ctl_store(cr0, 0, 0); + cr0_sync = cr0; + cr0_sync |= 0x00000200; + cr0_sync &= 0xFFFFF3AC; + __ctl_load(cr0_sync, 0, 0); + asm volatile ("STOSM 0(%1),0x01" + : "=m" (psw_mask) : "a" (&psw_mask) : "memory"); + /* Loop until driver state indicates finished request */ + while (sclp_running_state != sclp_running_state_idle) { + /* Check for expired request timer */ + if (timer_pending(&sclp_request_timer) && + sclp_get_clock() > timeout && + del_timer(&sclp_request_timer)) + sclp_request_timer.function(sclp_request_timer.data); + barrier(); + cpu_relax(); + } + /* Restore interrupt settings */ + asm volatile ("SSM 0(%0)" + : : "a" (&psw_mask) : "memory"); + __ctl_load(cr0, 0, 0); + __local_bh_enable(); +} + +EXPORT_SYMBOL(sclp_sync_wait); + +/* Dispatch changes in send and receive mask to registered listeners. */ +static inline void +sclp_dispatch_state_change(void) +{ + struct list_head *l; + struct sclp_register *reg; + unsigned long flags; + sccb_mask_t receive_mask; + sccb_mask_t send_mask; + + do { + spin_lock_irqsave(&sclp_lock, flags); + reg = NULL; + list_for_each(l, &sclp_reg_list) { + reg = list_entry(l, struct sclp_register, list); + receive_mask = reg->receive_mask & sclp_receive_mask; + send_mask = reg->send_mask & sclp_send_mask; + if (reg->sclp_receive_mask != receive_mask || + reg->sclp_send_mask != send_mask) { + reg->sclp_receive_mask = receive_mask; + reg->sclp_send_mask = send_mask; + break; + } else + reg = NULL; + } + spin_unlock_irqrestore(&sclp_lock, flags); + if (reg && reg->state_change_fn) + reg->state_change_fn(reg); + } while (reg); +} + +struct sclp_statechangebuf { + struct evbuf_header header; + u8 validity_sclp_active_facility_mask : 1; + u8 validity_sclp_receive_mask : 1; + u8 validity_sclp_send_mask : 1; + u8 validity_read_data_function_mask : 1; + u16 _zeros : 12; + u16 mask_length; + u64 sclp_active_facility_mask; + sccb_mask_t sclp_receive_mask; + sccb_mask_t sclp_send_mask; + u32 read_data_function_mask; +} __attribute__((packed)); + + +/* State change event callback. Inform listeners of changes. */ +static void +sclp_state_change_cb(struct evbuf_header *evbuf) +{ + unsigned long flags; + struct sclp_statechangebuf *scbuf; + + scbuf = (struct sclp_statechangebuf *) evbuf; + if (scbuf->mask_length != sizeof(sccb_mask_t)) + return; + spin_lock_irqsave(&sclp_lock, flags); + if (scbuf->validity_sclp_receive_mask) + sclp_receive_mask = scbuf->sclp_receive_mask; + if (scbuf->validity_sclp_send_mask) + sclp_send_mask = scbuf->sclp_send_mask; + spin_unlock_irqrestore(&sclp_lock, flags); + sclp_dispatch_state_change(); +} + +static struct sclp_register sclp_state_change_event = { + .receive_mask = EvTyp_StateChange_Mask, + .receiver_fn = sclp_state_change_cb +}; + +/* Calculate receive and send mask of currently registered listeners. + * Called while sclp_lock is locked. */ +static inline void +__sclp_get_mask(sccb_mask_t *receive_mask, sccb_mask_t *send_mask) +{ + struct list_head *l; + struct sclp_register *t; + + *receive_mask = 0; + *send_mask = 0; + list_for_each(l, &sclp_reg_list) { + t = list_entry(l, struct sclp_register, list); + *receive_mask |= t->receive_mask; + *send_mask |= t->send_mask; + } +} + +/* Register event listener. Return 0 on success, non-zero otherwise. */ +int +sclp_register(struct sclp_register *reg) +{ + unsigned long flags; + sccb_mask_t receive_mask; + sccb_mask_t send_mask; + int rc; + + rc = sclp_init(); + if (rc) + return rc; + spin_lock_irqsave(&sclp_lock, flags); + /* Check event mask for collisions */ + __sclp_get_mask(&receive_mask, &send_mask); + if (reg->receive_mask & receive_mask || reg->send_mask & send_mask) { + spin_unlock_irqrestore(&sclp_lock, flags); + return -EBUSY; + } + /* Trigger initial state change callback */ + reg->sclp_receive_mask = 0; + reg->sclp_send_mask = 0; + list_add(®->list, &sclp_reg_list); + spin_unlock_irqrestore(&sclp_lock, flags); + rc = sclp_init_mask(1); + if (rc) { + spin_lock_irqsave(&sclp_lock, flags); + list_del(®->list); + spin_unlock_irqrestore(&sclp_lock, flags); + } + return rc; +} + +EXPORT_SYMBOL(sclp_register); + +/* Unregister event listener. */ +void +sclp_unregister(struct sclp_register *reg) +{ + unsigned long flags; + + spin_lock_irqsave(&sclp_lock, flags); + list_del(®->list); + spin_unlock_irqrestore(&sclp_lock, flags); + sclp_init_mask(1); +} + +EXPORT_SYMBOL(sclp_unregister); + +/* Remove event buffers which are marked processed. Return the number of + * remaining event buffers. */ +int +sclp_remove_processed(struct sccb_header *sccb) +{ + struct evbuf_header *evbuf; + int unprocessed; + u16 remaining; + + evbuf = (struct evbuf_header *) (sccb + 1); + unprocessed = 0; + remaining = sccb->length - sizeof(struct sccb_header); + while (remaining > 0) { + remaining -= evbuf->length; + if (evbuf->flags & 0x80) { + sccb->length -= evbuf->length; + memcpy(evbuf, (void *) ((addr_t) evbuf + evbuf->length), + remaining); + } else { + unprocessed++; + evbuf = (struct evbuf_header *) + ((addr_t) evbuf + evbuf->length); + } + } + return unprocessed; +} + +EXPORT_SYMBOL(sclp_remove_processed); + +struct init_sccb { + struct sccb_header header; + u16 _reserved; + u16 mask_length; + sccb_mask_t receive_mask; + sccb_mask_t send_mask; + sccb_mask_t sclp_send_mask; + sccb_mask_t sclp_receive_mask; +} __attribute__((packed)); + +/* Prepare init mask request. Called while sclp_lock is locked. */ +static inline void +__sclp_make_init_req(u32 receive_mask, u32 send_mask) +{ + struct init_sccb *sccb; + + sccb = (struct init_sccb *) sclp_init_sccb; + clear_page(sccb); + memset(&sclp_init_req, 0, sizeof(struct sclp_req)); + sclp_init_req.command = SCLP_CMDW_WRITEMASK; + sclp_init_req.status = SCLP_REQ_FILLED; + sclp_init_req.start_count = 0; + sclp_init_req.callback = NULL; + sclp_init_req.callback_data = NULL; + sclp_init_req.sccb = sccb; + sccb->header.length = sizeof(struct init_sccb); + sccb->mask_length = sizeof(sccb_mask_t); + sccb->receive_mask = receive_mask; + sccb->send_mask = send_mask; + sccb->sclp_receive_mask = 0; + sccb->sclp_send_mask = 0; +} + +/* Start init mask request. If calculate is non-zero, calculate the mask as + * requested by registered listeners. Use zero mask otherwise. Return 0 on + * success, non-zero otherwise. */ +static int +sclp_init_mask(int calculate) +{ + unsigned long flags; + struct init_sccb *sccb = (struct init_sccb *) sclp_init_sccb; + sccb_mask_t receive_mask; + sccb_mask_t send_mask; + int retry; + int rc; + unsigned long wait; + + spin_lock_irqsave(&sclp_lock, flags); + /* Check if interface is in appropriate state */ + if (sclp_mask_state != sclp_mask_state_idle) { + spin_unlock_irqrestore(&sclp_lock, flags); + return -EBUSY; + } + if (sclp_activation_state == sclp_activation_state_inactive) { + spin_unlock_irqrestore(&sclp_lock, flags); + return -EINVAL; + } + sclp_mask_state = sclp_mask_state_initializing; + /* Determine mask */ + if (calculate) + __sclp_get_mask(&receive_mask, &send_mask); + else { + receive_mask = 0; + send_mask = 0; + } + rc = -EIO; + for (retry = 0; retry <= SCLP_MASK_RETRY; retry++) { + /* Prepare request */ + __sclp_make_init_req(receive_mask, send_mask); + spin_unlock_irqrestore(&sclp_lock, flags); + if (sclp_add_request(&sclp_init_req)) { + /* Try again later */ + wait = jiffies + SCLP_BUSY_INTERVAL * HZ; + while (time_before(jiffies, wait)) + sclp_sync_wait(); + spin_lock_irqsave(&sclp_lock, flags); + continue; + } + while (sclp_init_req.status != SCLP_REQ_DONE && + sclp_init_req.status != SCLP_REQ_FAILED) + sclp_sync_wait(); + spin_lock_irqsave(&sclp_lock, flags); + if (sclp_init_req.status == SCLP_REQ_DONE && + sccb->header.response_code == 0x20) { + /* Successful request */ + if (calculate) { + sclp_receive_mask = sccb->sclp_receive_mask; + sclp_send_mask = sccb->sclp_send_mask; + } else { + sclp_receive_mask = 0; + sclp_send_mask = 0; + } + spin_unlock_irqrestore(&sclp_lock, flags); + sclp_dispatch_state_change(); + spin_lock_irqsave(&sclp_lock, flags); + rc = 0; + break; + } + } + sclp_mask_state = sclp_mask_state_idle; + spin_unlock_irqrestore(&sclp_lock, flags); + return rc; +} + +/* Deactivate SCLP interface. On success, new requests will be rejected, + * events will no longer be dispatched. Return 0 on success, non-zero + * otherwise. */ +int +sclp_deactivate(void) +{ + unsigned long flags; + int rc; + + spin_lock_irqsave(&sclp_lock, flags); + /* Deactivate can only be called when active */ + if (sclp_activation_state != sclp_activation_state_active) { + spin_unlock_irqrestore(&sclp_lock, flags); + return -EINVAL; + } + sclp_activation_state = sclp_activation_state_deactivating; + spin_unlock_irqrestore(&sclp_lock, flags); + rc = sclp_init_mask(0); + spin_lock_irqsave(&sclp_lock, flags); + if (rc == 0) + sclp_activation_state = sclp_activation_state_inactive; + else + sclp_activation_state = sclp_activation_state_active; + spin_unlock_irqrestore(&sclp_lock, flags); + return rc; +} + +EXPORT_SYMBOL(sclp_deactivate); + +/* Reactivate SCLP interface after sclp_deactivate. On success, new + * requests will be accepted, events will be dispatched again. Return 0 on + * success, non-zero otherwise. */ +int +sclp_reactivate(void) +{ + unsigned long flags; + int rc; + + spin_lock_irqsave(&sclp_lock, flags); + /* Reactivate can only be called when inactive */ + if (sclp_activation_state != sclp_activation_state_inactive) { + spin_unlock_irqrestore(&sclp_lock, flags); + return -EINVAL; + } + sclp_activation_state = sclp_activation_state_activating; + spin_unlock_irqrestore(&sclp_lock, flags); + rc = sclp_init_mask(1); + spin_lock_irqsave(&sclp_lock, flags); + if (rc == 0) + sclp_activation_state = sclp_activation_state_active; + else + sclp_activation_state = sclp_activation_state_inactive; + spin_unlock_irqrestore(&sclp_lock, flags); + return rc; +} + +EXPORT_SYMBOL(sclp_reactivate); + +/* Handler for external interruption used during initialization. Modify + * request state to done. */ +static void +sclp_check_handler(struct pt_regs *regs, __u16 code) +{ + u32 finished_sccb; + + finished_sccb = S390_lowcore.ext_params & 0xfffffff8; + /* Is this the interrupt we are waiting for? */ + if (finished_sccb == 0) + return; + if (finished_sccb != (u32) (addr_t) sclp_init_sccb) { + printk(KERN_WARNING SCLP_HEADER "unsolicited interrupt " + "for buffer at 0x%x\n", finished_sccb); + return; + } + spin_lock(&sclp_lock); + if (sclp_running_state == sclp_running_state_running) { + sclp_init_req.status = SCLP_REQ_DONE; + sclp_running_state = sclp_running_state_idle; + } + spin_unlock(&sclp_lock); +} + +/* Initial init mask request timed out. Modify request state to failed. */ +static void +sclp_check_timeout(unsigned long data) +{ + unsigned long flags; + + spin_lock_irqsave(&sclp_lock, flags); + if (sclp_running_state == sclp_running_state_running) { + sclp_init_req.status = SCLP_REQ_FAILED; + sclp_running_state = sclp_running_state_idle; + } + spin_unlock_irqrestore(&sclp_lock, flags); +} + +/* Perform a check of the SCLP interface. Return zero if the interface is + * available and there are no pending requests from a previous instance. + * Return non-zero otherwise. */ +static int +sclp_check_interface(void) +{ + struct init_sccb *sccb; + unsigned long flags; + int retry; + int rc; + + spin_lock_irqsave(&sclp_lock, flags); + /* Prepare init mask command */ + rc = register_early_external_interrupt(0x2401, sclp_check_handler, + &ext_int_info_hwc); + if (rc) { + spin_unlock_irqrestore(&sclp_lock, flags); + return rc; + } + for (retry = 0; retry <= SCLP_INIT_RETRY; retry++) { + __sclp_make_init_req(0, 0); + sccb = (struct init_sccb *) sclp_init_req.sccb; + rc = service_call(sclp_init_req.command, sccb); + if (rc == -EIO) + break; + sclp_init_req.status = SCLP_REQ_RUNNING; + sclp_running_state = sclp_running_state_running; + __sclp_set_request_timer(SCLP_RETRY_INTERVAL * HZ, + sclp_check_timeout, 0); + spin_unlock_irqrestore(&sclp_lock, flags); + /* Enable service-signal interruption - needs to happen + * with IRQs enabled. */ + ctl_set_bit(0, 9); + /* Wait for signal from interrupt or timeout */ + sclp_sync_wait(); + /* Disable service-signal interruption - needs to happen + * with IRQs enabled. */ + ctl_clear_bit(0,9); + spin_lock_irqsave(&sclp_lock, flags); + del_timer(&sclp_request_timer); + if (sclp_init_req.status == SCLP_REQ_DONE && + sccb->header.response_code == 0x20) { + rc = 0; + break; + } else + rc = -EBUSY; + } + unregister_early_external_interrupt(0x2401, sclp_check_handler, + &ext_int_info_hwc); + spin_unlock_irqrestore(&sclp_lock, flags); + return rc; +} + +/* Reboot event handler. Reset send and receive mask to prevent pending SCLP + * events from interfering with rebooted system. */ +static int +sclp_reboot_event(struct notifier_block *this, unsigned long event, void *ptr) +{ + sclp_deactivate(); + return NOTIFY_DONE; +} + +static struct notifier_block sclp_reboot_notifier = { + .notifier_call = sclp_reboot_event +}; + +/* Initialize SCLP driver. Return zero if driver is operational, non-zero + * otherwise. */ +static int +sclp_init(void) +{ + unsigned long flags; + int rc; + + if (!MACHINE_HAS_SCLP) + return -ENODEV; + spin_lock_irqsave(&sclp_lock, flags); + /* Check for previous or running initialization */ + if (sclp_init_state != sclp_init_state_uninitialized) { + spin_unlock_irqrestore(&sclp_lock, flags); + return 0; + } + sclp_init_state = sclp_init_state_initializing; + /* Set up variables */ + INIT_LIST_HEAD(&sclp_req_queue); + INIT_LIST_HEAD(&sclp_reg_list); + list_add(&sclp_state_change_event.list, &sclp_reg_list); + init_timer(&sclp_request_timer); + /* Check interface */ + spin_unlock_irqrestore(&sclp_lock, flags); + rc = sclp_check_interface(); + spin_lock_irqsave(&sclp_lock, flags); + if (rc) { + sclp_init_state = sclp_init_state_uninitialized; + spin_unlock_irqrestore(&sclp_lock, flags); + return rc; + } + /* Register reboot handler */ + rc = register_reboot_notifier(&sclp_reboot_notifier); + if (rc) { + sclp_init_state = sclp_init_state_uninitialized; + spin_unlock_irqrestore(&sclp_lock, flags); + return rc; + } + /* Register interrupt handler */ + rc = register_early_external_interrupt(0x2401, sclp_interrupt_handler, + &ext_int_info_hwc); + if (rc) { + unregister_reboot_notifier(&sclp_reboot_notifier); + sclp_init_state = sclp_init_state_uninitialized; + spin_unlock_irqrestore(&sclp_lock, flags); + return rc; + } + sclp_init_state = sclp_init_state_initialized; + spin_unlock_irqrestore(&sclp_lock, flags); + /* Enable service-signal external interruption - needs to happen with + * IRQs enabled. */ + ctl_set_bit(0, 9); + sclp_init_mask(1); + return 0; +} |